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Hydrogen absorption properties of amorphous(Ni0.6Nb0.4-yTay)100-xZrx membranes

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Progress in Natural Science:Materials International 2017年第1期27卷 126-131页

作者： O.Palumbo F.Trequattrini N.Pal M.Hulyalkar S.Sarker d.chandra T.Flanagan M.dolan A.Paolone CNR-ISC U.O.S. La Sapienza department of Physics Sapienza University of Rome department of Chemical and Materials Engineering University of Nevada department of Chemistry University of Vermont CSIRO QCAT Energy 1 Technology CourtPullenvale

Ni based amorphous materials have great potential as hydrogen purification membranes. In the present work the melt spun(Ni0.6Nb0.4-yTay)100-xZrxwith y=0, 0.1 and x=20, 30 was studied. The result of X-ray diffraction spectra of the ribbons showed an amorphous nature of the alloys. Heating these ribbons below T drogen atmosphere（1-10 bar）, the amorphous structure was retained. The crystallization process was characterized by differential thermal analysis and the activation energy of such process was obtained. The hydrogen absorption properties of the samples in their amorphous state were studied by the volumetric method,and the results showed that the addition of Ta did not significantly influence the absorption properties, a clear change of the hydrogen solubility was observed with the variation of the Zr content. The values of the hydrogenation enthalpy changed from37 k J/mol for x=30 to9k J/mol for x=20. The analysis of the volumetric data provides the indications about the hydrogen occupation sites during hydrogenation, suggesting that at the beginning of the absorption process the deepest energy levels are occupied, while only shallower energy levels are available at higher hydrogen content, with the available interstitial sites forming a continuum of energy levels.

关键词： Amorphous Ni based alloy ribbons High temperature X-ray diffraction dTA Activation energy Crystallization temperature Hydrogen solubility

Flexible Covalent Organic Frameworks:design,Synthesis,and Applications

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CCS Chemistry 2024年第4期6卷 856-881页

作者： Chunqing Ji Chengjun Kang Bidhan chandra Patra dan Zhao department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117585

Structural flexibility is an intriguing characteristic observed in materials that endows them with dynamic properties,allowing for intelligent adaptation and deformation in response to varying *** organic frameworks(COFs),a promising class of crystalline porous polymers,have garnered significant attention due to their unique features,including well-ordered,predesignable,and tunable structures,as well as their light-weighted nature and high thermal/chemical *** flexibility into COFs offers a captivating pathway for developing advanced materials with dynamic properties and versatile *** flexible COF field is currently experiencing rapid expansion,and there is a growing need for systematic review articles that offer a comprehensive overview of the developments in this *** this mini-review,we delve into the factors that contribute to structural flexibility in COFs from the point of structural *** summarize and categorize various modes of achieving flexibility across different dimensions,and discuss the potential applications of flexible COFs in vapor/gas adsorption,sensing,and smart membrane separations;further,we highlight their prospects and future research advancement.

关键词： covalent organic frameworks framework flexibility inducing factors flexibility modes smart materials

CT结肠成像:计算机辅助检测作为第二与同步阅片者对具有一定CT结肠成像经验的普通放射科医生诊断结肠息肉的影响

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国际医学放射学杂志 2014年第5期 491-491页

作者： T.Mang L.Bogoni V.X.Anand d.chandra A.J.Curtin A.S.Lev-Toaff 孔祥 department of Biomedical Imaging and Image-guided Therapy Medical University of ViennaWaehringer Guertel 18-201090ViennaAustria

摘要目的评估运用计算机辅助检测(CAd)作为第二和同步阅片者来帮助具一定的CT结肠成像(CTC)经验的放射科医生诊断结肠息肉的有效性。方法 7名具有一定CTC

关键词：结肠成像 CTC 放射科结肠息肉辅助检测 CT 计算机

Oxygen Fugacity and Water Activity during Thermal Peak and Retrogression of Granulites around the Sarvapuram Area, Karimnagar Granulite Terrane, Andhra Pradesh, India

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Acta Geologica Sinica(English Edition) 2019年第6期93卷 1900-1908页

作者： P.chandra SINGH d.PRAKASH department of Earth Sciences Indian Institute of TechnologyPowaiMumbai400076India Centre of Advanced Study in Geology Banaras Hindu UniversityVaranasi221005India

The investigated area around Sarvapuram represents a part of the Karimnagar granulite terrane of the Eastern dharwar Craton, India. Garnet–bearing gneiss is hosted as enclaves, pods within granite gneiss and charnockite. It is largely made up of garnet, orthopyroxene, cordierite, biotite, plagioclase, K–feldspar, sillimanite and quartz. The peak metamorphic stage is represented by the equilibrium mineral assemblage i.e. garnet, orthopyroxene, cordierite, biotite, plagioclase, sillimanite and quartz. Breakdown of the garnet as well as preservation of the orthopyroxene–cordierite symplectite, formation of cordierite with the consumption of the garnet + sillimanite + quartz represents the decompressional event. The thermobarometric calculations suggest a retrograde P–T path with a substantial decompression of c. 3.0 kbar. The water activity(XH2 O) conditions obtained with the win TWQ program for core and symplectite compositions from garnet–bearing gneiss are 0.07–0.14 and 0.11–0.16 respectively. The quantitative estimation of oxygen fugacity in garnet–bearing gneiss reveal log f O2 values ranging from-11.38 to-14.05. This high oxidation state could be one of the reasons that account for the absence of graphite in these rocks.

关键词： metamorphic conditions oxygen fugacity water activity garnet–bearing gneisses Karimnagar granulite terrane India

TENSOR SUM ANd dYNAMICAL SYSTEMS

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Acta Mathematica Scientia 2014年第6期34卷 1935-1946页

作者： d.SENTHILKUMAR P.chandra KALA department of Mathematics Government Arts College(Autonomous)Coimbatore-641 018India

In this paper we introduce the concept of tensor sum semigroups. Also we have given the examples of tensor sum operators which induce dynamical system on weighted locally convex function spaces.

关键词： tensor sum composition operators multiplication operator dynamical systems seminorm operator valued mapping

Cu–Co–O nano-catalysts as a burn rate modifier for composite solid propellants

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defence Technology（防务技术） 2016年第4期12卷 297-304页

作者： d. Chaitanya Kumar RAO Narendra YAdAV Puran chandra JOSHI Space Engineering and Rocketry Birla Institute of Technology Mesra Ranchi 835215 India

Nano-catalysts containing copper–cobalt oxides(Cu–Co–O) have been synthesized by the citric acid(CA) complexing method. Copper(II) nitrate and Cobalt(II) nitrate were employed in different molar ratios as the starting reactants to prepare three types of nano-catalysts. Well crystalline nano-catalysts were produced after a period of 3 hours by the calcination of CA–Cu–Co–O precursors at 550 °C. The phase morphologies and crystal composition of synthesized nano-catalysts were examined using Scanning Electron Microscope(SEM), Energy dispersive Spectroscopy(EdS) and Fourier Transform Infrared Spectroscopy(FTIR) methods. The particle size of nano-catalysts was observed in the range of 90 nm–200 nm. The prepared nano-catalysts were used to formulate propellant samples of various compositions which showed high reactivity toward the combustion of HTPB/AP-based composite solid propellants. The catalytic effects on the decomposition of propellant samples were found to be significant at higher temperatures. The combustion characteristics of composite solid propellants were significantly improved by the incorporation of nano-catalysts. Out of the three catalysts studied in the present work, Cu Co-I was found to be the better catalyst in regard to thermal decomposition and burning nature of composite solid propellants. The improved performance of composite solid propellant can be attributed to the high crystallinity, low agglomeration and lowering the decomposition temperature of oxidizer by the addition of Cu Co-I nano-catalyst.

关键词： Metal oxides Nano-catalysts Solid propellant Burn rate Surface morphology Thermal analysis

Journey through the birth, growth and maturity of X-ray astronomy

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Research in Astronomy and Astrophysics 2019年第10期19卷 1-16页

作者： Prahlad.chandra Agrawal MU-dAE Centre of Excellence in Basic Sciences Mumbai University Campus at Vidhyanagari

In this biographical account, I recall my scientific journey that began in 1961 when I joined as a Physics Trainee in the BARC Training School and after one year course was admitted in TIFR as a Research Associate. during 1962–1967, I worked on determination of the He^3 /He^4 ratio in cosmic rays using a gas Cerenkov counter and also used a scintillation + solid Cerenkov detector to measure flux of protons and helium nuclei in primary cosmic rays. I also developed a large area scintillation-Cerenkov detector with a spark chamber between them for measuring charge composition of primary cosmic rays. I joined the X-ray astronomy programme in 1967 initiated by Prof. B. V. Sreekantan and played a leading role in developing a balloon borne hard X-ray instrument for studying time variability and energy spectra of cosmic X-ray sources. We carried out a series of balloon experiments and studied temporal intensity variation and energy spectra of X-ray objects like Sco X-1, Cyg X-1, etc. Results on rapid intensity changes and spectra appeared in a series of publications based on which I obtained a Ph.d. degree in 1972. Immediately afterwards, I joined Prof. Gordon Garmire at Caltech as a Research Fellow (a post-doctoral position) to work with him on the low energy component of HEAO A-2 experiment. The instrument was developed and successfully realised. Working on this satellite experiment was a thrilling experience which exposed me to the technical complexities of space instruments. The HEAO-1 satellite was launched in 1978. during 1978–1979, Guenter Riegler and I, working at JPL, reported detection of intense soft X-rays from several classes of extragalactic and Galactic objects like new BL Lacs, a new AM Her binary, coronal X-rays from active stars, etc. After returning to TIFR, I developed a rocket experiment with K. P. Singh to map the spatial and spectral distribution of the Soft diffuse X-ray Background. At the same time, I also designed 15 cm deep Xenon filled Proportio

关键词： TIFR-X-ray Astronomy by balloons-rockets and satellites-Indian Astronomy Satellite ASTROSAT

A numerical study of violent sloshing problems with modified MPS method

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Journal of Hydrodynamics 2017年第4期29卷 659-667页

作者： debadatta Jena Kishore chandra Biswal department of Civil Engineering National Institute of Technology

A numerical study on violent liquid sloshing phenomenon in a partially filled rectangular container is carried out by using moving particle semi-implicit（MPS） method. The present study deals with the implementation of five modifications all together over the original MPS method. The modifications include improved source terms for pressure Poisson equation, special approximation technique for the representation of gradient differential operator, collective action of mixed free surface particle identification boundary conditions, effecting Neumann boundary condition on solving the PPE and fixing judiciously the parting distance among particles to prevent collision. The suitability of the kernel function used in the original MPS method along with these five modifications is investigated for violent sloshing problems. The present model ensures a good agreement between numerical results with the existing experimental observations. The model is successfully applied to a partially filled tank undergoing horizontal sinusoidal excitation to compute the sloshing wave amplitudes and pressure on tank walls. The assessment of dynamic behaviour manifested in terms of base shear, overturning moment and impact pressure load exerted on tank ceiling induced by violent sloshing motion using MPS method is not reported in the open literature and has been efficiently carried out in the present study.

关键词： Sloshing particle method impact pressure base shear overturning moment

Analyzing driver's response to yellow indication subjected to dilemma incursion under mixed traffic condition

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第1期8卷 107-116页

作者： Ramesh chandra Majhi Velmurugan Senathipathi Traffic Engineering and Safety division CSIR-Central Road Research InstituteNew Delhi 110025India

Under mixed traffic conditions prevailing on Indian roads,drivers show complex response when faced with yellow signal because lane assignment gets dynamic in *** present study analyzes the effect of surrounding vehicles on response of the drivers while facing dilemma at *** dilemma zone definitions hold true in case of homogeneous traffic mix,a statistical analysis is performed to check the consistency across the definitions under mixed traffic *** study shows a significant difference in percentage of red light running in comparison to homogeneous traffic as reported by various *** carrying out the research,study locations are chosen in such a way to reflect diversity in road geometry,traffic composition and signal *** results deduced in this study indicate a strong correlation between the driver's decision making choice and the effect of presence of surrounding vehicle at the onset of yellow *** effect of critical time analysis has been found out to be one of the parameters other than critical distance in categorizing driver's aggressiveness while facing the yellow *** the process of identifying the statistical significance of dilemma zone definitions,it has been found that under heterogeneous traffic condition,drivers behave differently as compared to homogenous traffic when it comes to dilemma *** is observed that the percentage of vehicles crossing the intersection when faced with dilemma by violating the red light is 11.6%according to dilemma zone definition I whereas the definition II has yielded about 10.8%violation covering different vehicle *** above violation figures derived based on the above definition is somewhat higher as compared to homogeneous traffic condition which is observed to be of the order of 5%-6%.

关键词： Transportation engineering Mixed traffic dilemma dilemma zone Critical time